[Analysis of the clinical characteristics and species distribution of non-tuberculous mycobacteria in a general hospital].

Objective

To summarize the clinical characteristics and species distribution of nontuberculous mycobacteria(NTM).

Methods

We conducted a retrospectively chart review of 453 adult patients with 532 positive cultures with NTM diagnosed and treated in Peking Union Medical College Hospital from January 2014 to December 2018. The information including clinical findings, imaging and etiological data were obtained from clinical examination system. Among these 453 patients, 75 cases met the diagnostic criteria for NTM, with detailed clinical data, culture results and radiological images. Of these patients, 38 were males and 37 were females, with an average age of (50.8±16.2) years. Clinical manifestations, imaging features, NTM species and treatment were analyzed.

Results

Among 75 NTM patients, 43 cases (57.3%, 43/75) were infected with Mycobacterium avium Complex (MAC)/intracellular, 18 cases (24.0%, 18/75) with Mycobacterium turtle/abscess, and 7 cases (9.3%, 7/75) with Mycobacterium kansasii. Comorbidities existed in 64.0% patients (48/75). The top two common comorbidities were previous tuberculosis (25.3%, 19/75) infection and clinical bronchiectasis (18.7%, 14/75). After the respiratory disease (82.7%, 62/75), we identified bloodstream as the most frequent manifestation of NTM infection (25.3%, 19/75). MAC was often associated with infection in respiratory system and bloodstream, while rapidly growing mycobacteria (RGM) was more commonly detected in lymph nodes and skin and soft tissues. Cough/expectoration (77.4%, 48/62) was the most common clinical symptom of NTM disease, followed by fever and dyspnea. The frequent imaging findings were nodules (41.9%, 26/62), bronchiectasis (37.1%, 23/62), and fibrous cavities (24.2%, 15/62). In disseminated NTM disease, 94.7% (18/19) patients had underlying diseases and 89.5% (17/19) patients had long-term immunosuppression.

Conclusion

The most common NTM species was Mycobacterium avium/intracellular in our series. The predominant infected organ was the respiratory system. Previous tuberculosis history likely increased the risk of infection.